CVE-2015-0854 in Shutter
Summary
by MITRE
App/HelperFunctions.pm in Shutter through 0.93.1 allows user-assisted remote attackers to execute arbitrary commands via a crafted image name that is mishandled during a "Show in Folder" action.
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Analysis
by VulDB Data Team • 07/21/2019
The vulnerability identified as CVE-2015-0854 resides within the Shutter screenshot application version 0.93.1 and earlier, specifically within the App/HelperFunctions.pm module. This flaw represents a command injection vulnerability that occurs during the "Show in Folder" functionality when processing user-provided image names. The issue stems from inadequate input validation and sanitization mechanisms that fail to properly handle special characters or malicious payloads embedded within file names. Attackers can exploit this weakness by crafting specially formatted image filenames that, when processed through the vulnerable helper function, execute unintended system commands with the privileges of the application user. The vulnerability falls under the category of CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, making it a classic command injection flaw that has been consistently identified across numerous software applications.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with the capability to perform arbitrary actions on the affected system. When a user opens a maliciously crafted image file through the Shutter application and subsequently triggers the "Show in Folder" action, the application processes the filename without proper sanitization, allowing attackers to inject OS commands that execute in the context of the running application. This can potentially lead to complete system compromise, especially if the application runs with elevated privileges or if the user has administrative rights. The vulnerability is particularly concerning because it requires only user interaction to be exploited, making it a prime candidate for social engineering attacks where users might be tricked into opening malicious image files. The attack vector aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the execution of system commands through legitimate interfaces.
Mitigation strategies for CVE-2015-0854 should focus on implementing proper input validation and sanitization mechanisms throughout the application's codebase. The most effective approach involves sanitizing all user-provided input, particularly filenames and paths, before processing them within system command contexts. This can be achieved through the implementation of strict character filtering, escaping mechanisms, and the use of safe execution functions that properly quote and escape arguments. Additionally, the application should employ privilege separation techniques to ensure that even if exploitation occurs, the impact remains limited to the application's operational scope rather than the entire system. Security patches should be applied immediately to update to versions of Shutter that address this vulnerability, as the flaw exists in versions through 0.93.1 and likely affects earlier releases as well. Organizations should also consider implementing network-based protections such as intrusion detection systems that can identify and block malicious file transfers that might contain crafted filenames designed to exploit this vulnerability. The remediation process should include thorough code review of similar functions throughout the application to identify and address other potential command injection vulnerabilities that may exist in the codebase, ensuring comprehensive protection against similar attack vectors.